Jointing clips for insulated conductors

ABSTRACT

In a channel-type insulation-piercing insulated cable-jointing clip for use with a hand crimping tool, the insulating cover has, at the channel bottom, two bib-like end extensions with cut-outs for locating the two conductors to be joined in position for the crimping of the clip.

United States Patent 1191 Hilton et al.

JOlNTlNG CLIPS FOR INSULATED CONDUCTORS Inventors: John Leslie Hilton, Ringwood;

Arthur Manthorpe Faulkner, Swindon, both of England Assignee: Plessey Handel Und Investments A.G., Zug, Switzerland Filed: Jan. 23, 1973 Appl. No.: 326,165

Foreign Application Priority Data Jan, 28, 1972 Great Britain 4154/72 US. Cl. 174/84 C, 29/628, 29/630 F,

174/94 R, 339/97 C, 339/276 R int. Cl H02g 15/08 Field of Search 174/84 C, 84 R, 88 R, 90, 174/94 R; 339/95 R, 97 R, 97 C, 98, 276 R, 276 T, 223 R, 103 R, 105; 29/628, 629, 630-F 1 1 June 18, 1974 {56] References Cited UNITED STATES PATENTS 3,511,921 5/1970 Pasternak 174/88 R 3,621,117 11/1971 Antas et a1 ..174/84 C 3,715,456 2/i973 Faulkner 174/84C Primaiy Examiner-Darrell L. Clay Attorney, Agent, or Firm-Scrivener Parker Scrivener & Clarke [5 7] ABSTRACT In a channel-type insulation-piercing insulated cablejointing clip for use with a hand crimping tool, the insulating cover has, at the channel bottom, two bib-like end extensions with cut-outs for locating the two conductors to be joined in position for the crimping 0f the clip.

3 Claims, 3 Drawing Figures This invention relates to the jointing of insulated electrical conductors and has for an object to provide an improved channel-type jointing clip adapted for forming, by a crimping operation an insulated joint between two conductors placed side-by-side into the clip.

In telecommunication systems, more particularly in public telephone networks, a great number of pairs of insulated electrical conductors require to be joined together in an electrically conductive manner while preserving continuity of insulation so as to minimise the risk of spurious connections between adjacent conductors. This operation used to require a great amount of time as well as considerable skill of the operator.

In order to reduce the cost of establishing such connections, it has already been proposed to employ for the establishment of each joint a clip comprising a channel-type jointing clip of metal, into which the wires to be jointed electrically are placed side-by-side, and which is provided at its inner side with. insulationpiercing projections, while the outer side of the metal clip is covered with a layer of flexible insulating material so that when the channel walls are crimped-over against the channel bottom, with the insulated wires suitably positioned in the channel, the crimping opera tion will electrically interconnect the conductors while the insulating layer covering the channel ensures continuity of insulation along the conductor and protection against electrical contact between adjacent conductors. A jointing clip of this kind will hereinafter be referred-to as an insulated channel-type jointing clip.

In US. Pat. No. 3517804 issued June 30, 1970 and No. 3,715,456 issued Feb. 6, 1973, there are described and claimed particular forms of such channel-type insulated jointing clips which lend themselves to inexpensive and reliable manufacture, and which have been found wholly satisfactory when used in semi-automatic power-driven crimping machines. The use of such machines is often desirable, for example when forming the necessary end-to-end connections between the leads at the end of two adjoining newly-laid lengths of multicore telephone cable in a junction box, i.e., under conditions in which there is adequate room for securing a frame on which a power driven crimping machine is adjustably supported in convenient relation to the cable, and in which also a considerable number of junctions is to be established at the same occasion, thus making the time of mounting the frame with the machine worthwhile in comparison to the total time of its use.

There are however numerous occasions in which connections of a similar kind have to be established either at places at which the mounting of such semi-automatic machine is not practicable or at which only one or a few junctions are to be established at a time, so that the use a semi-automatic power-driven machine would require a disproportionate amount of setting-up time, or when such machine is not available and at which therefore the use of a hand-held and hand operated crimping tool is required. But although a junction established by the use of a jointing clip as described in either one of the abovementioned patents and crimped by such hand-held too] would be perfectly satisfactory if the conductors are placed into the clip in the appropriate positions and held in this position during the crimping, it has been found very difficult in practice to ensure the establishment and maintenance of this accurate positioning, more particularly in a confined space, because the operator is required to hold and manipulate the crimping tool with one of his hands, and only one hand therefore remains available for placing the wires into the clip and holding them in position while the crimping tool is being operated. The present invention has for a more specific object to provide an improved channel-type insulated jointing clip which greatly reduces these difficulties.

According to the invention the flexible insulating layer of an insulated channel-type jointing clip is, at each end of the clip, extended in the longitudinal direction either at the bottom wall or at each of the side walls of the channel, to form a projecting apron, and each apron is near the end of the metal jointing clip, provided with a cut-out in each lateral edge that faces a line at which two walls of the channel are joined, so that when the apron is bent-over at least partially across the profile of the channel, each of two wires resting in the channel to extend longitudinally thereof can be engaged in such cut-out to hold that wire in a predetermined position on the bottom of the metal clip and to retain it there when, by a subsequent crimping operation the channel walls are folded on to the bottom of the channel.

Preferably each cut-out extends from the edge in question, and preferably at each end of the channel a single apron is provided extending the flexible layer of insulation on the bottom wall of the metal jointing clip. Apart from this the insulated jointing clip of the present invention is preferably constructed as described and claimed in the said US. Pat. No. 3,715,450 the bottom wall of the insulating channel of the clip described inthe said Patent being extended at each end to form the two aprons.

In order that the invention may be more readily understood, two embodiments will now be described with reference to the accompanying drawings, in which FIG. 1 is a perspective view of one form of insulated jointing clip according to the present invention,

FIG. 2 similarly illustrated this jointing clip with two conductors inserted therein located in the required positions by the recesses of the two apron-like extensions, and

FIG. 3 is a view similarly to FIG. 2 but illustrating a modified form of the invention.

Referring now first to FIG. 1, the illustrated insulated channel-type jointing clip comprises a channel-type jointing clip 1 which consists of metal and is provided at its inner side with projecting spike portions 2 adapted to pierce the insulation of a pair of insulated conductor wires when these are placed side by side on the bottom of the channel and the channel is then crimped to fold the two side walls of the channel towards the channel bottom. Such crimping operation will therefore establish electrical connection between the metal conductors of the two'wires through the body of the channel-type jointing clip 1. In order to prevent electrical contact between adjacent metal jointing clips and thus between separate conductors, each metal jointing clip 1 is inserted in a channel3 of flexible insulating plastics material which completely covers the outer sides of the bottom and side walls of the channel, and which is doubled-back inwardly in U-formation at the free longitudinal edges of the side wallsas shown at 4, substantially throughout the length of the metal clip of the metal clip 1 so as to prevent the metal clip from being lifted out of the insulating channel and as to ensure insulating protection of the said longitudinal edges of the metal clip when the side walls of the metal clip have been folded inwardly by a crimping operation, the amount by which the doubled-back edges of the insulating channel extend towards the web of the channel being sufficiently small to permit the assembly of the jointing clip to be effected by forcing the metal clip 1 into the insulating channel 3 from. the open side of the channel profile at right engles to the web of the insulating channel, and then allowing the doubled-back edge portions 4 of the insulating channel to snap over the longitudinal edges of the channel-type metal clip 1. The side walls of the insulating channel 3 are arranged to project at both ends over the ends of the channel-type metal jointing clip 1. The insulated jointing clip as described up to this point is preferably identical in all respects to that described in the said US. Pat. No. 3,715,456. The clip according to the invention differs, however, from the clip described-in that specification by the fact that the bottom wall 5 of the insulating channel is extended at both ends longitudinally of the channel beyond the ends of the side walls 6 to form at each end an apron 7 having two lateral edges 8 which extend longitudinally of the channel so as to form approximate continuations of the two edges formed by the junctions of the side and bottom walls of the insulating channel 3. Each of these lateral edges 8 is provided with a U-shaped cut-out 9 at a point near the end of the metal clip 1 and of the channel side wall 6, this cut-out being so arranged that, when the apron 7 is bent-over at least partially across the profile of the channel, each of two insulated electrical conductor wires placed at the bottom of the channel-type metal clip 1 can be engaged in one of the cut-outs 9 so as to be located each near one of the junctions between the bottom and side walls of the channel.

FIG. 2 shows the same'jointing clip when thus assembled with the two wires 10 in position, and it will be readily appreciated that once the clip and wires have been assembled in this manner, the wires will be retained in their correct positions in the clip by the recesses 9 of the aprons 7 without the need of retaining them manually. The operator therefore has now both his hands free to insert the assembly as a whole into a hand crimping tool and then to complete the joint by operating the tool tov crimp the'connection.

FlG. 3'illustrates, similarly to FIG. 2, a modified form of jointing clip according to the present invention, with two wires retained in position for crimping. The jointing clip differs from that illustrated in FIGS. 1 and 2 by the fact that it is the side walls, and not the bottom wall, of the insulating channel 3 that are extended at the two ends of the metal jointing clip 1 to provide four aprons 11, one at each end of each side wall of the channel. All of these aprons 11 extend beyond the adjacent end 12 of the bottom wall of the insulating channel and each of them is provided at its bottom edge, near the adjacent end of the metal clip 1, with a U-shaped cut-out 13 which, when the apron 11 is at least partially bentover across the profile of the channel, can engage a conductor wire 10 and locate it in the required position near the junction between the bottom and one of the side walls of the channel-type metal jointing clip 1.

., Both forms of; insulated jointing clip described with reference tothe drawings may be manufactured in a manner closely resembling that described in the said US. Pat. No. 3,715,456, in which the insulation for the channel is made from a continuous channel of insulating plastic material having doubled-back edges; the metal jointing clips are inserted into the latter from the open side of the channel with sufficient longitudinal spacing to enable the apron-like extensions to be formed by cutting the channel at appropriate points of its length to provide the length of the apron or aprons, and cutting away the side walls, or the bottom wall, for the length of the apron or aprons, and forming the re cesses at the appropriate places. Alternatively an insulating channel foreach connector may be formed individually by moulding.

It will. be readily appreciated that the invention is not limited to all the details of the illustrated embodiments and that, for example,'while it is preferred to construct the jointing clip according to the invention, apart from the provision of the apron-like extensions, substantially as described in the said US. Pat. No. 3,175,456 the invention may, if desired, be alternatively applied to insulated'channel-type jointing clips of a different construction, so long as the insulation at the outer side of the channel-type metal jointing clip is of a suitably flexible nature to permit the formation and described use of the apron-like extensions.

What we claim is:

1. A clip for jointing insulated conductor wires which comprisestwo metal side walls substantially parallel to a first plane and a metal bottom wall disposed in a second plane normal to said first plane, said bottom wall being integrally jointed at its longitudinal edges with a longitudinal edge of each of said side walls respectively to form, jointly with said side walls, a channel'constituting a metal clip, said metal clip having insulationpiercing projections at the inner side of the channel and being covered at its outer side with a layer of flexible insulating material, wherein this insulating layer is, at each end of each channel wall that is disposed according to one of said planes, extended in the longitudinal direction of the channel to form a projecting apron extending beyond the ends of said clip, and each apron is near the end of the metal clip, and having a cut-out in each lateral edge that faces a line at which two walls of the channel are joined, so that, when the apron is bentover at least partially across the profile of the channel, one of two wires resting in the channel and extending longitudinally thereof can be engaged in said cut-out to be held by such engagement in a predetermined position on the bottom of the metal clip and retained in such position when, by a subsequent crimping operation, the said side walls are folded on to the bottom wall of the channel.

2. A jointing clipas claimed in claim 1 wherein said apron is end of the channel a single apron extending from the flexible layer of insulation on the bottom wall of the metal clip. e

3. A jointing clip asclaimed in claim 1, wherein said layer of insulating material is constituted by a channel of resiliently flexible insulating material whose flanges have their free longitudinal edges doubled-back inwardly of the channel in U-formation substantially throughout the length of the metal clip, the dimensions I the bottom of the channel being sufficiently small to permit the assembly of the jointing clip to be efiected by forcing the metal clip into the insulating channel from the open side of the channel profile, at right angels to the bottom of the insulating channel, then allowing the doubled-back edge portions of the insulating channel to snap over the longitudinal edges of the channel-type metal clip. 

1. A clip for jointing insulated conductor wires which comprises two metal side walls substantially parallel to a first plane and a metal bottom wall disposed in a second plane normal to said first plane, said bottom wall being integrally jointed at its longitudinal edges with a longitudinal edge of each of said side walls respectively to form, jointly with said side walls, a channel constituting a metal clip, said metal clip having insulation-piercing projections at the inner side of the channel and being covered at its outer side with a layer of flexible insulating material, wherein this insulating layer is, at each end of each channel wall that is disposed according to one of said planes, extended in the longitudinal direction of the channel to form a projecting apron extending beyond the ends of said clip, and each apron is near the end of the metal clip, and having a cut-out in each lateral edge that faces a line at which two walls of the channel are joined, so that, when the apron is bent-over at least partially across the profile of the channel, one of two wires resting in the channel and extending longitudinally thereof can be engaged in said cut-out to be held by such engagement in a predetermined position on the bottom of the metal clip and retained in such position when, by a subsequent crimping operation, the said side walls are folded on to the bottom wall of the channel.
 2. A jointing clip as claimed in claim 1 wherein said apron is end of the channel a single apron extending from the flexible layer of insulation on the bottom wall of the metal clip.
 3. A jointing clip as claimed in claim 1, wherein said layer of insulating material is constituted by a channel of resiliently flexible insulating material whose flanges have their free longitudinal edges doubled-back inwardly of the channel in U-formation substantially throughout the length of the metal clip, the dimensions of the insulating channel being such as to tightly embrace the metal clip with the doubled-back longitudinal edges of the insulating channel wrapped round the longitudinal edges of the side walls of the metal clip so as to prevent the metal clip from being lifted out of the insulating channel and as to ensure insulating protection of the said longitudinal edges of the metal clip when the side walls of the metal clip have been folded by such crimping operation, the amount by which the doubled-back edges of the insulating channel extend towards the bottom of the channel being sufficiently small to permit the assembly of the jointing clip to be effected by forcing the metal clip into the insulating channel from the open side of the channel profile, at right angels to the bottom of the insulating channel, then allowing the doubled-back edge portions of the insulating channel to snap over the longitudinal edges of the cHannel-type metal clip. 